Miniature lamp and receptacle therefor



July 19, 1966 K. HERRMANN ETAL 3,262,086

MINIATURE LAMP AND RECEPTACLE THEREFOR Filed March 27, 1964 2Sheets-Sheet 1 Fig.1b F

INVENTORS Karl Herrm nn Woltgang Ott By WP ATTORNEY July 19, 1966 K.HERRMANN ETAL 3,

MINIATURE LAMP AND RECEPTACLE THEREFOR Filed March 27, 1964 2Sheets-Sheet 2 INVENTORS Karl Herrmann Wolfgang Ott 4. ATTO RN EY UnitedStates Patent 3 262,086 MINIATURE LAMP Abil) RECEPTACLE THEREFUR KarlHerrmann and Wolfgang Ott, Augsburg, Germany,

assignors to Patent-Freuhand-Gesellschaft fur Electrische Gliihlampenm.b.H., Munich, Germany Filed Mar. 27, 1964, Ser. No. 355,367 Claimspriority, application Germany, Apr. 3, 1963, P 31,500 5 Claims. (Cl.339176) This invention relates to electrically operated lamps and moreparticularly to miniature flash lamps, being concerned primarily withthe base construction and contacts and to the receptacle with which thelamp may be utilized. The invention is involved with lamps havingelongated tubular envelopes of small bulb volume usually in the vicinityof one cubic centimeter, and to lamps utilizing a glass base molded asan integral part with the glass bulb.

It is recognized there have been, in the prior art, lamps of largercapacity than the lamps involved in this invention, that have employedglass bases, such use being extended to larger-capacity photo-flashlamps. The known prior art lamp consists, for instance, of a nearlycylindrical appendage of the bulb somewhat flattened at sides thereof toprovide two axially parallel opposite plane areas from which the currentin-leads come out to be extended around the rounded parts of the base tofunction as the base contacts. Such a base, however, cannot be used forminiature photoaflash lamps because the hollow body forming the baserepresents a too great dead volume within the lamp.

Again it may be said that there is, in the prior art, a glass base forphoto flash lamps of larger volume of well over one cubic centimetercapacity, which consists of a bulb having a flattened stem from thefront sides of which the current in-leads project, those in-leads thenbeing bent around different sides of the stem press like loops. Such abase, however, has the disadvantage of the length of the stem pressserving as the glass base having to be quite long and actually, in theminimum size bulbs in which it is capable of use, has a lengthpractically equal to or perhaps exceeding the length of the bulb portionof the lamp containing the light-producing medium. I

In its broad concept, the present invention proposes an improvedconstruction of flash lamp of practical character for small-volumelamps.

Likewise a general aspect of the invention is directed to a lamp havingan integral glass base with its bulb wherein the interior volume of thelamp is not increased at all by presence of the base therewith.

Somewhat more specifically, an object of the invention is to provide aminiature photo-flash lamp having an integral glass base of extremelyshort length in comparison to the total length of the lamp.

Corollary to the foregoing object, the invention is directed to theprovision of a photo-flash lamp with integral glass bulb and base, thetotal length whereof is essentially and little more than the length ofthe bulb.

Of similar nature, the invention seeks and attains provision of a baseof very small axial depth to perform at the same time the severalfunctions of sealing the bulb, of providing seal for the in-leads, ofsecurely positioning and protecting contacts for exterior electricalconnections, of orienting the lamp in its introduction into areceptacle, and of providing means for retaining the lamp in areceptacle.

In conjunction with the foregoing object, the invention accomplishes thefurther objective of preventing shortcircuit between the receptacleterminals when inserting the lamp into a receptacle.

The invention also includes provision of a receptacle of room-savingcharacter and minimum depth for utilization of the improved lamp.

Other objects, advantages, beneficial results and novel structuralfeatures will appear to persons skilled in the art to which theinvention appertains, both by direct recitation thereof and byimplication from the context, as the description proceeds.

Referring to the accompanying drawings, in which like numerals ofreference indicate similar parts throughout the several views;

FIGURE 1a is a bottom end view of a flash-lamp constructed in accordancewith the invention;

FIGURE 11) is a side elevation of the basal end of the lamp of FIG. 1a;

FIGURE 2 is a similar side elevation of a flash-lamp showing a modifiedconstruction of in-lead contacts;

FIGURE 3a is a diametric and axial section of a receptacle for use withflash lamps of FIGS. 1a, 1b and 2; and

FIGURE 3b is a top plan of said receptacle of FIG. 3a.

In the specific embodiment of the invention illustrated in saiddrawings, and first considering the showing thereof in FIGS. 1a and 1b,the flash-lamp comprises a hollow cylindrical glass bulb 1, which itwill be understood is closed as usual at its upper end in accordancewith usual practice by a domed end of glass in continuation of the glassside walls. The bottom end of the bulb is sealed with a glass flare 2which, in the completed lamp, constitutes a glass base made integralwith the bulb side wall as part of the fabricating process. That processis performed in a manner which produces a circumferential bulge orannular bead 3 the maximum diameter whereof is greater than the diameterof the cylindrical bulb 1, and coaxial with said bulb. Said flare, afterbeing incorporated as an integral part with said bulb and de- (finedexteriorly by said bead, comprises the base for the lamp and for themost part is solid glass, as a consequence of which it does not increasethe interior golume of the lamp beyond the normal capacity of the Thesaid flare 2 is generally flat at its exterior under surface 2a exceptfor a medial non circular protuberance 4, formed integrally therewith,of glass and projecting downwardly in a direction parallel to andincluding the axis 212 of the flare. Transversely to the axis 212, saidprotuberance 4 is shown as elongated but shorter in length than thediameter of the flare so does not extend to the periphery of the flare,said protuberance, furthermore, in cross-section being somewhatrectangular with semicylindrical ends. In a direction at right angles tothe long transverse dimension of the protuberance, the same is of lesswidth and the long side faces or flanks 4a thereof in conjunction withthe generally flat surface 2a of the said flare, may be said to providea declivity 26 at each flank of said protuberance 4 beneath tangentialconstruction line 2d.

For an appreciation by way of specific example of approximate dimensionsfor a bulb of substantially one cubic centimeter capacity, the bulb maybe in the close range of seven millimeters diameter and something overtwo centimeters in axial length, and used therewith is a bead of abouttwo and four-tenths millimeters axial depth and having maximum diameterof about eight millimeters. The axial height or depth of theprotuberance 4, and therefore the maximum depth of the associateddeclivities 20, might very properly be about one and a half millimeters,so that from the top of the flare 2 (where the bead 3 joins the bulb 1)to the bottom of the protuberance 4, the distance would be approximatelythree '2 a and nine-tenths millimeters. Said base may therefore be veryjustifiably referred to as relatively short or squatty as compared bothto its diameter and to the length of the lamp.

Current in-leads and 6, the inner ends whereof protrude into theinterior of bulb 1, are sealed in the said flare 2, and come out throughthe bottom surface thereof, each on an opposite side of protuberance 4adjacent the opposite flanks 4a thereof and accordingly within what hasbeen termed above as the declivities 2c formed by said surface andprotuberance. Immediately at the point of exit of the said in-leads fromsaid surface, they are bent down into engagement with said surface,preferably in a direction transverse to the protuberance so as toconstitute electrical contacts 5a and 6a respectively. The contacts thusformed are separated by the protuberance 4 so as to be incapable ofmaking a short circuit, and are in a protected location in saiddeclivities 20. It may be mentioned here, that an exhaust tubulation 7,which may be metallic, extends from the interior of the bulb through themiddle of the protuberance, and at proper sequence of manufacturingoperations on the lamp, is sealed off in well-known manner, namely,after the lamp has gone through the exhausting and gas-filling stages.It may also be added here, that if so desired, one of the in-leads maybe made tubular and used as the exhaust tubulation during manufacture ofthe lamp, and sealed off and then utilized as the in-lead and contact.

If so desired, the in-leads may have a construction indicated in FIG. 2,differing from that shown in FIGS. and 1b, by provision of in-leads 8and 9 which remain straight, but with stubby protruding ends functioningas contacts situated in the above-described declivities 2c. Otherwisethe foregoing description also applies to the showing of FIG. 2,inclusive of the suggestion of possible use of one of the in-leads as anexhaust tubulation.

Comment may also be made here, that while the foregoing description hasarbitrarily referred to use of the invention with respect to miniaturephotoflash lamps, the invention is not to be understood as restrictedthereto, as it is also applicable to miniature incandescent lamps, inwhich event the axial height of the glass base, constituted by flare 2and protuberance 4, may be even less than the dimension mentioned above.Photoflash lamps generally have a gas filling under pressure, whereasminiature incandescent lamps are gas-filled at a lower pressure.

Flash devices, which include mounts for flash-lamp receiving receptaclesand electrical circuit closing means for controlling energy from asuitable source, such as an electrical battery, are known in the priorart for use with flash-lamps heretofore available on the market. Aspecial construction of receptacle for use in such devices is requiredfor the flash-lamp of the present invention, and an example of a novelreceptacle for this particular use is illustrated in FIGS. 3a and 3b.

In said showing of receptacle, the mount employed and designated bynumeral 10a, is one provided with a hole 10 of appropriate size andshape symmetrical in opposite diametric directions with respect to acentral axis. Two semi-circular clamping jaws 11, 12 adapted to closetoward each other to provide a circular cavity therebetween coaxial withsaid hole 10, are mounted to slide laterally within the confines of thehole. To coordinate positioning and operation of said jaws 11, 12, thesame are provided with an exterior annular groove 14a in which islocated an elastic retainer such as the generally annular but expandablespring 14 shown. Said retainer is rendered expandable by provision of aradially outwardly directed loop 14b therein at one side and by adiscontinuity at the opposite side, the discontinuity ends 140 beingalso projected radially outwardly. Said loop 14b and ends 140 projectover a part 1012 of the mount 10a and will prevent depression of thejaws 11, 1 2 when the lamp is inserted. It may also be mentioned thatthe mount may be conveniently provided with clips 20, 21 projectinginwardly over the top edges of the jaws proximate to their facing edgesfor retaining the jaws permanently in the hole 10 of the mount.

The jaws 11, 12 are provided on their inner arcuate faces each with aninwardly projecting semi-annular shoulder 13 which, when said jaws areclosed together, form a complete annular shoulder coaxial to andprojecting into the central cavity within the jaws. The jaws are ofelectrically non-conductive material.

Projecting under said jaws 11 and 12 are resilient terminals,respectively 15, 16, of leaf-spring type, said terminals extending in acommon diametric direction but separated from each other at their innerends by a gap 17 commensurate with the width of the lamp protuberance 4.The width of said terminals 15, 16 is adapted to prevent the said lampprotuberance 4 from being pushed down therebelow anywhere but throughsaid gap 17, and form upper surfaces on which said protuberance may berotated until it registers with the gap. The distance in an axialdirection from the under side of said shoulder 13 to the bottom plane ofthe jaws 11, 12 corresponds to the depth of the bulge or bead 3 of thelamp, so that when the downwardly exposed lamp contacts engage anddepress the resilient terminals, said bead will be engaged under saidshoulder. In that position of the lamp, the two jaws are resilientlypressed against the periphery of the base thereof rendering the shoulder13 effective to retain the lamp from escape and maintain the in-leadcontacts in resilient electrical engagement with the leaf-springterminals 15, 16.

Too much bending of the leaf-spring terminals 15, 16, when the lamp ispressed into the receptacle, is prevented by provision of limitingsupports 18, 19 thereunder. These said supports may conveniently be ofstiffer material than the spring terminals, for example may be brassbars, and conform in width and length to the corresponding dimensions ofthe said terminals. Each spring terminal and its contiguous limitingsupport 18 or 19 extend radially outwardly beyond the jaw-receiving hole10 and are secured by rivets 10d or in other suitable manner, to theflash device mount 10a thereat. Each limiting support 18, 19 has apermanent slope inwardly and downwardly with respect to its associatedjaw so as to permit the desired resilient flexing of the springterminals.

A receptacle constructed in accordance with the above description foruse with the specific examples of dimensions of flash-lamp also givenabove, namely, one having a base the total height of which issubstantially three and nine-tenths millimeters in height, will requireonly a total depth of receptacle of five and four-tenths millimeters.Consequently, the receptacle requires very little space foraccommodation in the flash device.

As a further modification of flash-lamp base (not shown) for a moldedglass base formed from the flare in accord with the above disclosure,the protuberance 4 thereof may be longitudinally split or divided intotwo sections providing a valley or declivity between those sections. Thein-leads could then be located between the sections within thatdeclivity and would be even more fully protected than in the hereinpreviously described construction.

We claim:

1. An electric lamp, more particularly a miniature photoflash lamp, withelongated tubular bulb and molded glass flare made as the lamp base,characterized in that at the transition of molded glass base and bulbthere is formed an annular shoulder, said base having a protuberanceintegral therewith projecting outwardly from the end surface of the basein the direction of the lamp axis, and said protuberance having anon-circular crosssection providing side flanks extending in planeschordal to the tubular configuration of the lamp and establishing adeclivity bounded at one side by said flanks and at another side by saidend surface of the base, and current in-leads projecting from said baseat a location contiguous to said flanks of the protuberance and entirelyin said de-clivity for protection thereby from damage and disruption.

2. An electric lamp as claimed in claim 1, characterized in that theouter ends of the said current in-leads are bent sharply at their exitfrom said base and are carried along adjacent to the end surface of thebase as short stumps entirely in said declivities.

3. In combination, an electric lamp as claimed in claim 1, a flashdevice therefor comprising a receptacle for receiving said base of saidelectric lamp, said receptacle having two semi-circular clamping jaws inan elongated 'hole of said flash device, elastic means holding said jawstogether but permitting lateral sepanation of the jaws for introductionof said lamp base therebetween, said jaws when closed together providingan annular shoulder and cavity at their inner sides, two electricterminal springs at the under ends of said jaws directed toward eachother, said springs having a gap between opposed ends thereof with thewidth of said gap at least as great as the width of said protuberance ofthe lamp base preventing the said protuberance from being pushed downbelow said opposed ends except when registering lengthwise with saidgap, and the distance between the annular shoulder of the clamping jawsand said terminal springs corresponding nearly References Cited by theExaminer UNITED STATES PATENTS 2,415,902 2/1947 Noel 339 X 2,602,1057/1952 VVelch et a1. 339228 2,715,216 8/1955 Howenstine 339255 X2,891,231 6/1959 Gregson et a1. 33993 2,904,716 9/1959 Malrn et a1339144 X FOREIGN PATENTS 657,270 9/ 1951 Great Britain.

EDWARD C. ALLEN, Primary Examiner.

W. DONALD MILLER, Examiner.

1. AN ELECTRIC LAMP, MORE PARTICULARLY A MINIATURE PHOTOFLASH LAMP, WITHELONGATED TUBULAR BULB AND MOLDED GLASS FLARE MADE AS THE LAMP BASE,CHARACTERIZED IN THAT AT THE TRANSITION OF MOLDED GLASS BASE, AND BULBTHERE IS FORMED AN ANNULAR SHOULDER, SAID BASE HAVING A PORTUBERANCEINTEGRAL THEREWITH PROJECTING OUTWARDLY FROM THE END SURFACE OF THE BASEIN THE DIRECTION OF THE LAMP AXIS, AND SAID PROTUBERANCE HAVING ANON-CIRCULAR CROSSSECTION PROVIDING SIDE FLANKS EXTENDING IN PLANESCHORDAL TO THE TUBULAR CONFIGURATION OF THE LAMP AND ESTABLISHING ADECLIVITY BOUNDED AT ONE SIDE OF SAID FLANKS AND AT ANOTHER SIDE BY SAIDEND SURFACE OF THE BASE, AND CURRENT IN-LEADS PROJECTING FROM SAID BASEAT A LOCATION CONTIGUOUS TO SAID FLANKS OF THE PROTUBERANCE AND ENTIRELYIN SAID DECLIVITY FOR PROTECTION THEREBY FROM DAMAGE AND DISRUPTION.